Lake Union is a lake in King County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.

Are there boat ramps on Lake Union?

Lake Union has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sunnyside Avenue. Public access is listed as yes.

Can I fish at Lake Union?

Lake Union has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Washington's fish and wildlife agency, so check its current regulations before you go.

Lake Union

King County, Washington757 acresView map Directions

No nutrient or algae sampling on record from Washington Ecology for this lake.

Area

757 acres

Surface area

Impaired · Toxic inorganics
Public access

See the measurements Directions Where to stay

Lake Union in King County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Surface area: 757 acres.

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Lake Union is a 757-acre lake in King County, Washington. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, WA Ecology. Methodology: how these readings are compared.

What Lake Union is good for

From access and monitoring records, not editorial picks.

Boat launch1 documented ramp

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Lake Union is listed impaired under Clean Water Act §303(d) (IR 4B) for toxic inorganics. Check local advisories before you swim.

Whether Lake Union is safe to swim in today is a call for the Washington State Department of Ecology and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Lake Union

These are the measurements Washington Ecology publishes for Lake Union, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

No clarity data. TSI undefined.

Ask about Lake Union

Answers come straight from the public measurements and survey records on this page.

Lake Details

Surface area

757 acres

Public access

Yes

Listed by Washington Ecology

No bathymetric survey has been published for Lake Union, so its depth is not documented here.

Recreation & Access

Boat Landings

Yes

Public Access

Sunnyside AvenuePublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Stays via Stay22

Stays near Lake Union

Compare lakeside cabins, hotels, and vacation rentals near Lake Union in King County, Washington — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

Top-rated places to stay near Lake Union

Prices for Oct 16–18, 4 adults. Change dates on the map below.

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Planning a trip? Cabins and lodging at Lake Union → · more Washington lake trips

Follow Lake Union’s readings

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Fishing Lake Union

→ Lake Union fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Lake Union is officially listed as impaired under Clean Water Act §303(d) in the 2018 EPA reporting cycle (IR category 4B).

Causes of impairment

Toxic inorganics

Designated uses not supporting: Aquatic life.

Source: EPA ATTAINS assessment unit WA47122G3E3_SE · Official waterbody report

Nearby Lakes in King County

Green Lake2.6 miView →Lake Washington Ship Canal2.3 miView →Lake Washington3.6 miView →Burien Lake—View →Phantom Lake10.3 miView →Angle Lake20 ft clear—View →

Frequently asked questions about Lake Union

Where is Lake Union?: Lake Union is a lake in King County, Washington. Its water-quality measurements are published by Washington Ecology and shown on this page as reported.
What is the water quality of Lake Union?: Lake Union in King County, Washington has water-quality measurements published by Washington Ecology, shown here as reported. Surface area: 757 acres.
Is Lake Union safe to swim in?: Nutrient and algae readings are not a swimming clearance. Lake Union is listed impaired under Clean Water Act §303(d) (IR 4B) for toxic inorganics. Check local advisories before you swim.
Are there boat ramps on Lake Union?: Lake Union has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Sunnyside Avenue. Public access is listed as yes.
Can I fish at Lake Union?: Lake Union has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Washington's fish and wildlife agency, so check its current regulations before you go.